1. Field of the Invention
This invention relates generally to the field of molding vehicle hulls.
2. Description of Related Art
Various composite materials for vehicle hulls and processes of forming hulls of vehicles are known in the art. Several hulls in the marine industry incorporate molding processes for the surface elements of the shell of the vehicle. Also, several boats incorporate filling of an inner and outer shell with a core material.
U.S. Pat. No. 5,372,763 issued Dec. 13, 1994 to Hordis (xe2x80x9cHordisxe2x80x9d) describes a method of forming a transom for a boat. Hordis teaches the use of offset keys to space an inner and an outer transom.
A method of molding a composite framed resin article is described in U.S. Pat. No. 3,711,581 issued Jan. 16, 1973 to Fowler, Jr. et al. (xe2x80x9cFowlerxe2x80x9d). Fowler teaches a molded article with spaced rods between the layers of the articles to provide support.
U.S. Pat. No. 5,861,119 issued Jan. 19, 1999 to Merser (xe2x80x9cMerserxe2x80x9d) teaches a method of forming structural panel assemblies. Merser incorporates parallel structural assemblies secured by a foam adhesive.
A boat hull including molding hull structure is taught in U.S. Pat. No. 5,634,425 to MacDougall (xe2x80x9cMacDougallxe2x80x9d). MacDougall includes a plurality of longitudinally extending stiffening members.
U.S. Pat. No. 5,421,283 to Bruggemann describes a type of lightweight boat construction that incorporates a PVC pipe frame.
A method for molding large plastic unitary core boats is described in U.S. Pat. No. 4,953,494 to McClendon, Jr. (xe2x80x9cMcClendonxe2x80x9d). In McClendon, the inner core of the boat is molded separately from a matching outer ection.
U.S. Pat. No. 4,065,337 to Alter et al. (xe2x80x9cAlterxe2x80x9d) teaches a molding process. In Alter, formed sheets that comprise the shell of the hull must rest on frames during manufacture.
Reinforced structural panels are taught in U.S. Pat. No. 3,342,665 to Shannon, and U.S. Pat. No. 272,663 to Durant describes a method of building veneer boats.
The prior art does not teach or suggest a method of structurally bonding two hull sections to one another prior to the introduction of foam.
The prior art references do not teach a hull molding process that teaches the bonding of two hull sections before the introduction of foam. The prior art does not teach the use of an adhesive to form a connector between the two sections of the hull. Also, the prior art references do not teach a method of bonding two shell portions of a hull together while the hull is still in the molds, and then introducing foam while the shell portions are in the mold. Stringers, or braces, are generally required in the forming of a vehicle hull. What is needed in the art is a method of forming a foam-filled hull which does not use stringers.
This invention generally relates to a composite material that is to be used for vehicle hulls. There are several methods of forming hulls available. However, the processes generally include the use of stringers, which add to labor costs and uncertainty in the marriage between the two outer layers of the hull. Furthermore, without stringers, in the formation of a foam-center hull the top layer may squeeze against the lower layer, and there would be insufficient volume between the layers for the foam to be introduced between the layers. Alternatively, the expansion of the foam may cause a bond between a top layer and a bottom layer to be pulled apart.
The process of the present invention provides for the molding of a top and a bottom layer. After the top layer and the bottom layer are formed in molds, an adhesive is placed between mating portions of the top and bottom pieces, and the molds are closed together. After the molds are closed, the adhesive operates to form a connector between the top piece and the bottom piece, forming a single piece from the top and bottom layers, with at least one central cavity formed by the closing of the top piece to the bottom piece. While the mold is still closed, foam is introduced into the cavity, forming a core within the cavity. Since the molds are still in place when the foam is introduced, and the adhesive has connected the top piece with the bottom piece. With the connector in place, the expansion of the foam does not force the single piece apart.
In accordance with these and other objects that will become apparent hereinafter, the instant invention will now be described with particular reference to the accompanying drawings.